The broadhead is the last three inches of everything you did right, or wrong, on the way to the shot. Pick the wrong one for your setup and a good hit turns marginal. Here is how to choose between fixed-blade and mechanical heads, and what grain weight to run.
Fixed-blade broadheads
A fixed-blade head has blades that do not move. That is its whole advantage: nothing to fail, nothing to deploy, maximum structural strength for bone and hard angles. Fixed blades tend to penetrate deeper because no energy is spent opening the head, which is why heavy, slower, high-poundage setups and traditional-leaning shooters lean fixed.
The trade-off is flight. Those exposed blades catch air and expose any tuning flaw. A fixed blade demands a well-tuned bow and a correctly spined, well-built arrow. Get that right and a fixed blade is devastating and dead reliable. Get it wrong and you will watch broadheads plane away from your field points.
Fixed blades favor: higher poundage, well-tuned bows, hunters who want maximum reliability and penetration, shots where bone is likely.
Mechanical (expandable) broadheads
A mechanical head flies with its blades closed, then opens on impact. Because it flies like a field point, it is more forgiving of a setup that is not perfectly tuned, and it usually delivers a wider cut. That is why fast, flatter-shooting compound setups often shoot mechanicals well.
The cost is penetration and a moving part. Energy goes into opening the blades, so mechanicals generally penetrate less than a comparable fixed blade, and deployment can occasionally fail. On a strong setup with a well-built head, that risk is small; on a light-poundage setup or a bad-angle hit, it matters more.
Mechanicals favor: average-to-fast compound setups, hunters who want field-point-like accuracy, situations where a wide cut is the priority and penetration is adequate.
100 grain or 125 grain?
Grain weight is about matching the point weight you built and tuned your arrows around, not picking a bigger number for the sake of it.
- 100 grain is the default for most modern compound setups. It keeps arrow weight and speed in a familiar window and is the most common broadhead weight sold.
- 125 grain adds front-of-center weight for penetration and can steady a heavy hunting arrow, at a small cost in speed and trajectory. It suits heavier builds and shooters chasing penetration.
The key point: if you tuned your arrows with a 100-grain field point, sight in and hunt with a 100-grain broadhead. Changing point weight changes your dynamic spine and your point of impact. Read the spine guide for why.
The part nobody can skip: tuning
Neither head flies right on an untuned bow. Broadheads reveal tuning and spine problems that field points hide. Before you trust any broadhead: build your arrows to the correct spine, get your rest and center-shot right, and paper-tune. The Custom Arrow Builder gets your spine and point weight matched, and the BeeReal paper tuner confirms flight before opening day.
Bottom line
Fixed blades win on reliability and penetration but demand a tuned setup. Mechanicals win on accuracy and cut width but give up some penetration and add a moving part. Match your grain weight to the point weight you tuned around, then tune before you trust it. Shop broadheads and build the arrow to carry them.